I'm confused in Apex Specialist and do not understand how to test scheduled job that uses a callout.

Hi 

I'm confused in Apex Specialist. 

One of the requirements is to create a unit test WarehouseCalloutServiceTest. 

There is a condition: 

"Ensure that your code operates as expected in the scheduled context by validating that it executes after Test.stopTest() without exception. 

 Also assert that a scheduled asynchronous job is in the queue. The test classes for the callout service and scheduled test must also have 100% test coverage." 

So I must use `System.schedule` 

@isTestpublic class WarehouseCalloutServiceTest {
	@isTest	static public void warehouseCalloutServiceTest() {
		Test.startTest();
		Test.setMock(HttpCalloutMock.class, new WarehouseCalloutServiceMock());
		// Schedule the test job
		String jobId = System.schedule(
			'WarehouseCalloutServiceTest',
			'0 0 0 15 3 ? 2042',
			new WarehouseSyncSchedule()
		);
		Assert.isNotNull(jobId, 'JOB ID must be not null.');
		Test.stopTest();
		// Now schedulled job is finished and I can test result via Assert
		...
		Assert...

Now let's look at the `WarehouseCalloutServiceTest` class 

public class WarehouseSyncSchedule implements Schedulable {
    public void execute(SchedulableContext ctx) {
        WarehouseCalloutService srv = new WarehouseCalloutService();
        srv.updateProducts(); // there is a callout inside this method
     }
}

the solution does not work, it throws an exception `System.CalloutException: Callout from scheduled Apex not supported`. 

So I must use asynchronous queue 

    public void execute(SchedulableContext ctx) {
        WarehouseCalloutService srv = new WarehouseCalloutService();
        System.enqueueJob(srv);
    }

public class WarehouseCalloutService implements Queueable, Database.AllowsCallouts {
	public void execute(QueueableContext context) {
		this.updateProducts();  // there is a callout inside this method
 	}
}

And now I have 100% test coverage, but any asserts do not pass. 

" All asynchronous calls made after the startTest method are collected by the system. When stopTest is executed, all asynchronous processes are run synchronously." 

So `WarehouseCalloutServiceTest.execute` will be ran at the moment of `Test.stopTest()` because `System.schedule` is wrapped in startTest/stopTest. 

`WarehouseCalloutService` will be enqueued but `WarehouseCalloutService.execute` will be never ran because `System.enqueueJob` is not wrapped in startTest/stopTest. 

So any Asserts will be passed. 

What is wrong? 

Regards, 

Alexander 

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